1. Field of the Disclosure
The present disclosure relates to a patterned retarder for a three-dimensional image display device, and more particularly, to a method of fabricating a patterned retarder where fabrication process is simplified.
2. Discussion of the Related Art
Recently, according to a user's request for a display device displaying a three-dimensional image having an actual feeling, three-dimensional display devices have been researched and developed. In general, a stereoscopic image expressing a three-dimension is displayed using a principle of stereovision through eyes. Accordingly, a three-dimensional image display devices that display an image of a stereoscopic effect using a binocular disparity due to a separation distance of eyes, e.g., about 65 mm have been suggested.
In general, a three-dimensional image display device includes a display panel displaying an image, a patterned retarder attached to outer surface of the display panel and a pair of glasses selectively transmitting the image passing through the patterned retarder. For example, a liquid crystal panel may be used as the display panel. The patterned retarder polarizes two-dimensional images from the liquid crystal panel differently. For example, a right-eye image and a left-eye image of the two-dimensional images may be polarized to have a right circularly polarization state and a left circularly polarization state, respectively.
The patterned retarder may be fabricated through a complex process. FIG. 1A to 1D are cross-sectional views showing a method of fabricating a patterned retarder according to the related art. In FIG. 1A, a light orientation film 20 having a plurality of disordered polymer side chains is formed on a substrate 10 by coating and curing a polymeric material using a coating apparatus 90. For example, the polymeric material may have a property such that polymer side chains are aligned along one direction in response to an ultraviolet (UV) ray.
In FIG. 1B, the substrate 10 having the light orientation film 20 is disposed in a heat treating apparatus 95 and a dry process where the substrate 10 is heated for several seconds to several minutes is preformed so that a solvent in the light orientation film 20 can be removed.
In FIG. 1C, a first photo mask 70 having a transmissive area TA and a blocking area BA is disposed over the light orientation film 20 and a first polarized UV ray is irradiated onto the light orientation film 20 through the transmissive area TA of the first photo mask 70. As a result, the first polarized UV ray is selectively irradiated onto the light orientation film 20 to form a first oriented region 21 having a first orientation state along a first direction. For example, the first polarized UV ray may be irradiated onto a region corresponding to one of a right-eye image column and a left-eye image column so that the polymer side chains of the region are aligned along the first direction, while the other region where the first polarized UV ray is not irradiated has polymer side chains randomly aligned. Accordingly, the light orientation film 20 has the first oriented region 21 where the polymer chains are aligned along the first direction and a non-oriented region where the polymer chains are randomly aligned by irradiation of the first polarized UV ray.
In FIG. 1D, a second photo mask 72 having a transmissive area TA and a blocking area BA is disposed over the light orientation film 20 and a second polarized UV ray is irradiated onto the light orientation film 20 through the transmissive area TA of the second photo mask 72. The transmissive area TA and the blocking area BA of the second photo mask 72 correspond to the non-oriented region and the first oriented region 21, respectively, of the light orientation film 20. As a result, the second polarized UV ray is selectively irradiated onto the light orientation film 20 to form a second oriented region 23 having a second orientation state along a second direction perpendicular to the first direction. For example, the second polarized UV ray may be irradiated onto a region corresponding to the other one of the right-eye image column and the left-eye image column so that the polymer side chains of the region are aligned along the second direction.
Although not shown, a liquid crystal layer is formed on the orientation film 20 having the first and second oriented regions 21 and 23 and the liquid crystal layer is cured with a UV ray and a heat to form a patterned retarder.
However, since the patterned retarder is fabricated through a coating step for the orientation film 20, a dry step for the orientation film 20, two irradiation steps for the first and second oriented regions 21 and 23, a coating step for the liquid crystal layer and a UV curing step and a baking step for the liquid crystal layer, the fabrication process of the patterned retarder is complicated and the complicated fabrication process causes increase in fabrication cost.